MRI for lower back problems deemed 'overused'

Britain's Prime Minister David Cameron (L) speaks with professors Nick Fox and Martin Rossor as he stands next to a Magnetic resonance imaging (MRI) machine at the National Hospital for Neurology and Neurosurgery in London.

More than half of outpatient lumbar spine MRI scans weren't appropriate, with a particularly poor record of ordering by family physicians, researchers found.

When analyzed by an expert panel, 29% of MRI referrals to two large teaching hospitals were deemed inappropriate and a further 27% were of "uncertain value," Derek Emery, MD, of the University of Alberta in Edmonton, and colleagues found.

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Only 34% of lower back scans ordered by family physicians were considered appropriate compared with 58% ordered by physicians in other specialties, the group reported online in JAMA Internal Medicine in a research letter.

"Eliminating inappropriate scans and some of uncertain value could reduce the harm that accrues from unneeded investigations and result in significant cost savings," they wrote.

The findings weren't a surprise, Emery's group acknowledged.

Imaging for low back pain made the top five list of overused tests and treatments for both the American Academy of Family Physicians and American College of Physicians in the "Choosing Wisely" campaign.

Lumbar spine scans have risen dramatically to account for about a third of all MRI done in some regions, despite the poor correlation between its findings and clinical signs and symptoms, Emery and colleagues noted.

"Overuse is driven by many factors, including patient expectations, physician concerns about litigation, and lack of physician accountability for cost," they concluded. "Solutions will require strict adherence to appropriate guidelines and better education of patients."

The current study of requests for MRIs at two large Canadian teaching hospitals also examined scans of the head for headache but found better referral characteristics.

Among 1,000 requisitions examined over a set period by an expert panel nominated by Canadian specialty societies, 83% were considered appropriate without much variation among specialties.

The rest were evenly split between inappropriate indications and those of uncertain value.

"Most of the patients in our study referred for MRI of the head for headache had already been pre-screened with a CT scan, likely explaining the high rate of appropriate head MRIs," Emery's group suggested.

How appropriate the CT scans were wasn't assessed.

The only indication for lumbar spine MRI among the 1,000 outpatient referrals examined that routinely received a rating of "appropriate" by the expert panel was postoperative leg or back pain.

However, these accounted for only 17% of the lumbar spine MRI orders. The rest were three times more likely to receive an uncertain or inappropriate rating than to be judged appropriate.

Among the subspecialties, neurosurgeons were most likely to order appropriately (76%), whereas less than half of referrals by neurologists and orthopedic surgeons were deemed appropriate.

One limitation was that the majority of the lumbar spine MRI orders (64%) didn't have enough information on the original requisition to determine appropriateness.

"This has implications to study validity insofar as we had to seek out information from other sources," the researchers pointed out.

They also cautioned that their study couldn't address underuse of MRI and wasn't population based, "so extrapolation to other health systems should be done cautiously."